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    <title>ShellCheck: SC2322 – In arithmetic contexts, `((x))` is the same as `(x)`. Prefer only one layer of parentheses.</title>
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    <h1>SC2322 – ShellCheck Wiki</h1>
    <a href="https://github.com/koalaman/shellcheck/wiki/SC2322">See this page on GitHub</a>
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    <h2
id="in-arithmetic-contexts-x-is-the-same-as-x-prefer-only-one-layer-of-parentheses">In
arithmetic contexts, <code>((x))</code> is the same as <code>(x)</code>.
Prefer only one layer of parentheses.</h2>
<h3 id="problematic-code">Problematic code:</h3>
<div class="sourceCode" id="cb1"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb1-1"><a href="SC2322.html#cb1-1" aria-hidden="true" tabindex="-1"></a><span class="va">value</span><span class="op">=</span><span class="va">$((</span> ((<span class="va">offset</span> <span class="op">+</span> <span class="va">index</span>)) <span class="op">*</span> <span class="dv">512</span> <span class="va">))</span> </span></code></pre></div>
<h3 id="correct-code">Correct code:</h3>
<div class="sourceCode" id="cb2"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb2-1"><a href="SC2322.html#cb2-1" aria-hidden="true" tabindex="-1"></a><span class="va">value</span><span class="op">=</span><span class="va">$((</span> (<span class="va">offset</span> <span class="op">+</span> <span class="va">index</span>) <span class="op">*</span> <span class="dv">512</span> <span class="va">))</span></span></code></pre></div>
<h3 id="rationale">Rationale:</h3>
<p>ShellCheck found doubly nested parentheses in an arithmetic
expression. While the syntax for an arithmetic expansion is
<code>$((..))</code>, this does not imply that parentheses in the
expression should also be doubled. <code>(x)</code>, <code>((x))</code>,
and <code>(((x)))</code> are all identical, so you might as well use
only one layer of parentheses.</p>
<h3 id="exceptions">Exceptions:</h3>
<p>This is a stylistic suggestion. If you prefer keeping both
parentheses, you can <a href="ignore.html">ignore</a> this message.</p>
<h3 id="related-resources">Related resources:</h3>
<ul>
<li>Help by adding links to BashFAQ, StackOverflow, man pages, POSIX,
etc!</li>
</ul>
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